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Post by ross128 on Oct 28, 2016 16:13:10 GMT
Since the only purpose of the reactor is to allow you to mount radiators, it doesn't have to generate any appreciable power. A purpose-built reactor could probably be made by setting all sliders to their minimum value, and then nudging up until the game lets you install it on a ship. An RTG might be a good option too, since it has fewer components in theory it should be possible to make it smaller at its minimum size. I haven't optimized a reactor yet, but that was my eventual intent. Don't RTGS have a hard cap cost of 3k though? As for the radiators, I for some reason was thinking osmium was more expensive than tungston. Have to go fix that. Also, KKDRM is a *nice* name folks. ______________________________________________________________________________________________________ After messing around with it, it looks like it's not a real hard-cap. It's just that none of the cheap nuclear fuels seem to actually produce power in an RTG (except Polonium 210, which generates 57kW of heat with just one kilogram and has a very low melting point, quite difficult to cool until we can use less than a kg of it). So you end up having to use something expensive like Strontium-90, and that's where all the cost comes from. So if you just want the smallest, lightest source of radiator hardpoints and cost is no object, an RTG works quite well because you can make a functional Strontium-90 RTG that weighs just a hair over a kilogram. The problem is Strontium-90 itself costs an arm and a leg. Some of the fuels I'm not sure why they're even in there. Tritium for example can never make a usable RTG in-game because you'll always get the "fuel will melt" error (obviously this isn't a problem IRL, because there we're quite aware that Tritium is a gas). Thorium-210, with just a couple nW/kg of heat, can never produce a large enough temperature gradient to activate the thermocouple (though I wonder if that's a bug). Also, Pu-244's price is bugged. I'm pretty sure it's not supposed to cost 4.14Zc (ZettaCredits!) per kilogram. I think some of these prices might be a result of RTGs having no "enrichment" slider, so the game is treating them as "100% pure" and it's breaking the enrichment-cost scaling formula. The smallest functional reactor I can make seems to be 2.88kg for 353c, using 0.72% enriched U-233 dioxide (so it's 99.28% depleted uranium). It's 1kg of fuel, 1kg of control rods (both seem to be effective minimums, you can technically set both to 0 but the reactor won't work without them), and the rest is the coolant loop (mostly the thermocouple). |
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Post by someusername6 on Oct 28, 2016 16:25:59 GMT
That seems to be about the lower limit, yes. My current best at minimizing a fission reactor weight (after seeing this thread) is only slightly smaller, at 2.81kg and 311c.
ThermoelectricFissionReactorModule 190 W Thermoelectric Fission Reactor
ReactorCoreDimensions_m 0.1 0.1
NuclearReactor
Coolant Hydrogen
Moderator Pyrolytic Carbon
ModeratorMass_kg 0
Fuel Depleted Uranium
FuelMass_kg 1
FuelEnrichment_Percent 0.97
ControlRodComposition Boron
ControlRodMass_kg 1
NeutronReflector Boron
ReflectorThickness_m 0
AverageNeutronFlux__m2_s 1e+017
InnerTurbopump
Composition Boron Nitride
PumpRadius_m 0.01
RotationalSpeed_RPM 94
ThermocoupleInnerDimensions_m 0.1 0.1
Thermocouple
PTypeComposition Nickel Chromium Iron
NTypeComposition Molybdenum
Length_m 0.001
ThermocoupleExitTemperature_K 1000
OuterCoolant Hydrogen
OuterTurbopump
Composition Lithium
PumpRadius_m 0.01
RotationalSpeed_RPM 2
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Post by dwwolf on Oct 28, 2016 16:52:29 GMT
Science! in action.
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Post by lawson on Oct 28, 2016 19:39:15 GMT
Okay, so here's my current design of KKDRM. <snip> That's awesome! Looks like your initial missiles are expensive enough that a micro-NTR engine would be worth using. (there are several good designs floating around this thread and the missile thread) The greater ISP is likely to offset having a 2.4-5Kg engine that costs in the 300c-1Kc range. Should be able to get comparable acceleration as well. As an aside, I'd love to add "self destruct" charges to any NTR engine or fission generator. I bet most of the light weight ones would make good warheads when imploded. |
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Post by dragonkid11 on Oct 29, 2016 1:33:09 GMT
Okay, I think I have one problem with KKDRM.
If the enemy craft shot down one during accelerating phase, the missile is set to chase after closest heat source so....
Yeah, they all homed in on the downed missiles.
That's kinda a problem.
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Post by wafflestoo on Oct 30, 2016 19:37:03 GMT
I'm not sure if I should post this or not, the thread seems to be firmly into missile territory and this is hardly a super weapon. It is super broken though so I thought I'd share anyway   RG-1a3 Attack Drone. Basically a hot-rodded stinger drone armored with silica aerogel and armed with a 12kw railgun  12kw 1mm Railgun. This thing is broken, 12kw power input, muzzle energy is in the 25kj range and a total energy output of 670kw. Probably not all that impressive considering some of the more broken things people have posted, but I figure that the more data we can give the dev the better. Attachments:
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Post by targetx on Oct 30, 2016 21:53:34 GMT
Up your fluorine:methane ratio to 1 and you get over 4km/s from that engine
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Post by wafflestoo on Oct 30, 2016 23:20:13 GMT
I originally had it that way, but dropped it to reduce the amount of fluorine tankage needed. 4km/s drones seems to be plenty anyway.
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Post by dragonkid11 on Oct 30, 2016 23:44:34 GMT
I prefer to keep my drone at 5 km and maybe some extra endurance drone at 6 km.
I'm also trying to make sure that they finish their ammo before their fuel tank is expended.
EDIT:
You know, basis of reducing as much cost as possible.
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Post by wafflestoo on Oct 31, 2016 2:32:32 GMT
I'll play with it, but I kind of remember that stochiometric didn't boost total performance that much compared to just increasing the tankage.
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Post by wafflestoo on Oct 31, 2016 19:40:17 GMT
Okay, so as a base-line test I doubled the fuel tankage to see how much improvement that would get me:  +1.6km/s for an additional 13t of mass Then, as suggested I went for the stochiometric mixture without changing the engine bell shape:  +2.4km/s perfomance boost! Okay, I wasn't expecting it to be that good. But now it masses just about double what the base-line drone did. I'm not too happy about that for operational reasons since that means fewer can be carried for the same carrier size and they double the demand on the carrier's fluorine reserves. For maximum silliness, I swapped out the methane fuel for hydrogen:  an additional +1.1km/s boost over the X2, but still masses +13t heavier than the stock RG-1 and now it doesn't carry the same fuel supply as the carrier which will further complicate operational issues. I might play with smaller Methane tank sizes (I've been trying not to do that to avoid part-menu Kessler syndrome but sometimes sacrifices must be made). |
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Post by wafflestoo on Oct 31, 2016 19:50:24 GMT
More silliness, I monkeyed with the engine bell shape to go-for-broke on the exhaust velocity:   managed another 380m/s of dV, hardly seems worth it though  One last test unit, stochiometric fuel mixture and a custom 950kg methane tank:  1.7t lighter with nearly the same dV and a little cheaper as well. I'm not sure I like the shorter burn time though considering the AI behavior. I might have to try it in battle regardless and see if it makes any significant difference. (sorry for the double-post, it won't let me attach more than three images per post). |
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Post by Rocket Witch on Oct 31, 2016 23:35:17 GMT
Made a super fuel economy hydrogen NTR. Now you too can spew over 300kW of radioactive exhaust across the solar system for a whole day straight.  |
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Post by someusername6 on Oct 31, 2016 23:55:49 GMT
Here's a Xenon Resistojet. It's main purpose is decorative -- look at this beautiful blinding yellow for the exhaust -- but I suppose the thrust:mass ratio is alright.  |
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Post by dragonkid11 on Nov 1, 2016 2:01:25 GMT
I just realized that it was a shame that we can't make change to the fire rate mechanism of all guns types.
We can only use aluminium, which can get really heavy despite it's light weight.
Of course, we don't really know how fire rate mechanism work but if there's a way to optimize it, that would be nice.
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